BaseAudioContext.createBufferSource()

The createBufferSource() method of the BaseAudioContext Interface is used to create a new AudioBufferSourceNode, which can be used to play audio data contained within an AudioBuffer object. AudioBuffers are created using BaseAudioContext.createBuffer or returned by BaseAudioContext.decodeAudioData when it successfully decodes an audio track.

Syntax

var source = baseAudioContext.createBufferSource();

Returns

An AudioBufferSourceNode.

Example

In this example, we create a two second buffer, fill it with white noise, and then play it via an AudioBufferSourceNode. The comments should clearly explain what is going on.

Note: You can also run the code live, or view the source.

var audioCtx = new (window.AudioContext || window.webkitAudioContext)();
var button = document.querySelector('button');
var pre = document.querySelector('pre');
var myScript = document.querySelector('script');

pre.innerHTML = myScript.innerHTML;

// Stereo
var channels = 2;
// Create an empty two second stereo buffer at the
// sample rate of the AudioContext
var frameCount = audioCtx.sampleRate * 2.0;

var myArrayBuffer = audioCtx.createBuffer(2, frameCount, audioCtx.sampleRate);

button.onclick = function() {
  // Fill the buffer with white noise;
  //just random values between -1.0 and 1.0
  for (var channel = 0; channel < channels; channel++) {
   // This gives us the actual ArrayBuffer that contains the data
   var nowBuffering = myArrayBuffer.getChannelData(channel);
   for (var i = 0; i < frameCount; i++) {
     // Math.random() is in [0; 1.0]
     // audio needs to be in [-1.0; 1.0]
     nowBuffering[i] = Math.random() * 2 - 1;
   }
  }

  // Get an AudioBufferSourceNode.
  // This is the AudioNode to use when we want to play an AudioBuffer
  var source = audioCtx.createBufferSource();
  // set the buffer in the AudioBufferSourceNode
  source.buffer = myArrayBuffer;
  // connect the AudioBufferSourceNode to the
  // destination so we can hear the sound
  source.connect(audioCtx.destination);
  // start the source playing
  source.start();
}

Specifications

Specification Status Comment
Web Audio API
The definition of 'createBufferSource()' in that specification.
Working Draft  

Browser compatibility

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidEdge MobileFirefox for AndroidOpera for AndroidiOS SafariSamsung Internet
Basic supportChrome Full support 10
Prefixed
Full support 10
Prefixed
Prefixed Requires the vendor prefix: webkit
Edge Full support YesFirefox Full support 25IE No support NoOpera Full support 22
Full support 22
Full support 15
Prefixed
Prefixed Requires the vendor prefix: webkit
Safari Full support 6
Prefixed
Full support 6
Prefixed
Prefixed Requires the vendor prefix: webkit
WebView Android Full support YesChrome Android Full support 33Edge Mobile Full support YesFirefox Android Full support 26Opera Android Full support YesSafari iOS No support NoSamsung Internet Android ?

Legend

Full support  
Full support
No support  
No support
Compatibility unknown  
Compatibility unknown
Requires a vendor prefix or different name for use.
Requires a vendor prefix or different name for use.

See also

Document Tags and Contributors

Contributors to this page: fscholz, nylki, Jedipedia, chrisdavidmills, erikadoyle, teoli
Last updated by: fscholz,